Contrary to popular belief, bass heads are not just guitar heads without reverb. Bass amps are tasked with delivering perfectly clean low, mid, and high frequencies into everything from a tweeter (you don't find them on guitar amps) to the reactive loads and huge motors of 15' bass speakers. And they need to sound great night after night, session after session. This challenge, along with the fact that Hartke engineers were not going to leave the powering of their premium cabinets to just any bass head, led to the development of the Hartke HD Series, with tube and FET preamp sections for unlimited tone variation, the LH Series, with Class A tube preamps and truckloads of power, and the new TX Series, lightweight powerhouses with Tone Stack EQ's and Variable Shape Circuit for studio quality tone control.